Spaceflight Insider

PSLV booster soars into space with fleet of 20 satellites

Liftoff of PSLV-C34. (Click to enlarge) Photo Credit: ISRO

India has successfully launched its flagship PSLV rocket carrying a record number of 20 satellites. The launch occurred as planned at 9:26 a.m. local time (03:56 GMT) on June 22 from the Second Launch Pad at the Satish Dhawan Space Centre in Sriharikota.

The mission, designation PSLV-C34, was conducted by the Indian Space Research Organisation (ISRO) and was initially scheduled for launch in April 2016. It surpasses India’s previous record of the most satellites lofted into space during one flight, set April 28, 2008, when a PSLV-CA rocket delivered ten satellites into orbit.

Powered by its six strap-on boosters, the PSLV-XL rocket began its short vertical ascent until it started heading in a southeasterly direction. As usual during the initial phase of the PSLV flight, the vehicle was accelerated by only its four ground-lit boosters until 25 seconds on the mission clock. Then the remaining duo of air-lit boosters were ignited to continue the rocket’s ascent.

Liftoff of PSLV-C34.

PSLV-C34 engine ignition on launch pad. Photo Credit: ISRO

The ground-lit boosters separated from the launch vehicle at one minute and 10 seconds after liftoff. Approximately 22 seconds later, the rocket discarded its two air-lit boosters, which was followed by the separation of the first stage around one minute and 48 seconds into the flight.

Afterward, the rocket’s second stage assumed control over the mission, accelerating the vehicle for about two-and-a-half minutes. During this phase of the mission, the rocket’s protective payload fairing was jettisoned, exhibiting the swarm of 20 satellites attached to the fourth stage.

The rocket’s third stage ignited its engine at four minutes and 22 seconds after launch. It boosted the launch vehicle for nearly four minutes until it separated from the rocket.

Next, the fourth stage took control over the flight, leading the mission for slightly more than eight minutes, in order to deliver the payload into a 314-mile (505-kilometer) polar Sun-synchronous orbit (SSO), inclined 97.48 degrees.

At 17 minutes and seven seconds into the flight, ISRO’s CartoSat-2C Earth-observing satellite was deployed. It was the mission’s primary passenger, placed at the top of the payload stack.

With a weight of 1,604 pounds (727.5 kilograms), CartoSat-2C is based on the IRS-2 bus and has two solar arrays – which generate up to 986 watts of power – and two lithium-ion batteries. It is expected to be operational for up to five years.

The spacecraft is equipped with a single panchromatic camera capable of providing scene-specific spot imagery. The data from the satellite will be useful for cartographic applications, urban and rural infrastructure development and management, as well as coastal land use and regulation.

The imagery will also be helpful in utility management like road network monitoring, water distribution, the creation of land use maps, precision study, change detection to bring out geographical and human-made features, and various other Land Information System (LIS) and Geographical Information System (GIS) applications.

Thirty-five seconds after the deployment of CartoSat-2C, the rocket’s fourth stage released the two other significantly smaller Indian satellites: SathyabamaSat and Swayam.

Built by the Sathyabama University in Chennai, the SathyabamaSat is a two-unit CubeSat, weighing 3.3 pounds (1.5 kilograms). The miniature satellite, equipped with an infrared spectrometer, will measure the densities of greenhouse gases.

Swayam is a one-unit CubeSat built by the College of Engineering in Pune. It has a mass of about 2.2 pounds (1 kilogram). The spacecraft is expected to provide a point-to-point messaging service for the HAM radio community.

After the deployment of all three spacecraft for India, an Indonesian Earth observation satellite, named LAPAN-A3, separated from the fourth stage at 18 minutes and 22 seconds into the flight.

With a weight of 264 pounds (120 kilograms), the LAPAN-A3 spacecraft will be used for land, natural resources, and environment monitoring. It will be operated by the country’s National Institute of Aeronautics and Space (LAPAN).

Nearly at the same time when LAPAN-A3 detached from the fourth stage, the BIROS (Berlin Infrared Optical System) Earth-observing satellite was deployed. With a weight of 286 pounds (130 kilograms), it is the second heaviest payload of the PSLV-C34 mission. The spacecraft, operated by the German Aerospace Center (DLR), will be used to detect high-temperature events like forest fires. The satellite is expected to offer its services for about three years.

At exactly 19 minutes after liftoff, two other satellites were injected into orbit. The Maritime Monitoring and Messaging Micro-Satellite (M3MSat) is a communications spacecraft, weighing around 187 pounds (85 kilograms). Operated by the Canadian Space Agency (CSA), it will collect and study the Automatic Identification System (AIS) signals from the low-Earth orbit (LEO).

Photo Credit: ISRO

PSLV-C34 ascending toward the sky. Photo Credit: ISRO

The second satellite released at T+19 minutes is the U.S. spacecraft called SkySat-C1. With a weight of about 242 pounds (110 kilograms), the satellite is an Earth-imaging spacecraft built by Space Systems Loral (SSL). It will be operated by Terra Bella (formerly known as Skybox Imaging), a Google subsidiary for about six years. The satellite is designed to provide a sub-meter resolution imagery and HD video.

Twenty seconds later, another Canadian satellite was inserted into orbit. The 56-pound (25.5-kilogram) GHGsat spacecraft, operated by GHGsat Inc., is designed for Earth observation purposes. It will measure atmospheric concentration of greenhouse gases.

At 20 minutes and 20 seconds into the flight, the PSLV-C34 mission started releasing its last payload – a set of 12 three-unit CubeSats for the San Francisco-based Planet Labs. The constellation of Dove Satellites (also known as Flock-2P) will be used for Earth observation purposes. Each spacecraft weighs around 10.36 pounds (4.7 kilograms) and is designed to be operational for up to three years.

“This is a very exciting day for us,” commented Mike Safyan, director of launch and regulatory affairs at Planet. “Adding 12 satellites with the latest technologies to our fleet operating in Sun Synchronous Orbit will significantly increase our capacity for imagery collection.”

Every Flock satellite is fitted with a telescope and a frame CCD camera to provide imagery utilized in environmental, humanitarian, and business applications. The last satellite of the constellation was deployed at 26 minutes and 30 seconds after launch.

“CubeSats like the Dove continue to push the boundaries of what commercial small satellite technology looks like today,” said Curt Blake, president of Spaceflight. “Coupling them with our integrated launch services and the PSLV rocket, which continues to be one of the most routine and reliable avenues for us to launch our customers’ satellites, makes it easier and more affordable for organizations like Planet to execute their space missions.”

The mission did not end when all the spacecraft were fully deployed into space. ISRO plans to re-ignite the rocket’s fourth stage engine, 50 minutes after the separation of the last satellite. The engine will burn for about five seconds. Afterward, it will be shut down for 50 minutes and then re-ignited for another five seconds. These maneuvers are necessary for ISRO to check the ability of the fourth stage to place multiple satellites into different orbits using just a single rocket on future missions.

The four-stage PSLV booster is India’s most reliable launch vehicle. The rocket has been used to deliver more than 40 satellites into space for some 19 countries. PSLV is capable of lofting up to 3.25 metric tons to low-Earth orbit and about 1.42 metric tons to a geosynchronous transfer orbit (GTO).

The rocket uses an Earth-storable, liquid-fueled rocket engine for its second stage, known as the Vikas engine; it was developed by the Liquid Propulsion Systems Centre. The third stage of the PSLV is powered by a solid rocket motor that provides the upper stage’s high thrust after the atmospheric phase of the mission. The fourth stage is composed of two Earth-storable liquid-fueled engines.

The 144-foot (44-meter) tall XL version of the PSLV, which was used for Wednesday’s mission, is the upgraded variant of the rocket in its standard configuration. Its thrust is increased by the addition of more powerful, stretched strap-on boosters than on the standard version.

The vehicle has a mass of 320 metric tons at liftoff and uses the larger strap-on motors (PSOM-XL) that provide the capability of hoisting heavier payloads into orbit. PSOM-XL uses the larger, 3.2-foot (1-meter) diameter, 44-foot (13.5-meter) length motors. This version of the rocket carries 12 metric tons of solid propellants instead of the nine metric tons that were used on an earlier configuration of the PSLV.

The PSLV rocket in its XL configuration was launched for the first time Oct. 22, 2008, when it sent India’s Chandrayaan-1 lunar probe toward the Moon.

Wednesday’s mission was India’s fourth launch this year. The country’s next flight is currently scheduled to take place in July when a PSLV rocket will send ISRO’s Resourcesat-2A and ScatSat-1 satellites into orbit. However, the exact date of that launch has yet to be announced.

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Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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